如何顶部处理在棱镜

Question

    public class ModelA : BaseViewModel 
    { 
     public override void OnNavigatedTo(NavigationParameters { 
      param = parameters.GetValue("param"); 
     } 

     private async void Execute(){ 
      var p = new NavigationParameters(); 
      p.Add("wo", param); 

      await _navigationService.NavigateAsync("Page2", p); 
     } 
    } 

左后卫的按钮在第2页浏览模式

    public override async void OnNavigatedTo(NavigationParameters parameters) 
    { 
      Param = parameters.GetValue("param"); 
    } 

    public override void OnNavigatedFrom(NavigationParameters parameters){ 
     var p = new NavigationParameters(); 
     p.Add("param", Param); 

     _navigationService.NavigateAsync("Page1", p); 

     //_navigationService.GoBackAsync(p,true); 

    } 

当我按下左上角的返回按钮，我打了OnNavigatedFrom但是当在第1页VM，击中后在的OnNavigatedTo，参数是空

Answer 1

看看这篇文章，可能对你有用：

LINK